Heavy payload parachute ground disconnecting device

ABSTRACT

The present invention relates to a heavy payload parachute ground disconnecting device. The device comprises an actuator for keeping a holding mechanism in a locked position during a predetermined time interval and after elapse of the predetermined time interval for releasing the holding mechanism when a force acting on the actuator is below a predetermined threshold. A latch mechanism releases a link assembly connected to the payload when itself being released from the holding mechanism. In the holding position the latch mechanism transfers a predetermined portion of a payload force for acting on the actuator within an operational range of the same. The device is highly advantageous by providing a simple, yet highly flexible, design for numerous payload ranges.

This application claims benefit from U.S. Provisional Patent Application No. 60/723,437 filed Oct. 5, 2005 the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to the field of parachute accessories, and in particular to a device for automatically disconnecting a heavy parachuted payload from a parachute upon landing.

BACKGROUND OF THE INVENTION

In parachuting a payload from an airplane it is important that the parachuted payload is securely connected to the parachute during descent. It is also important that the payload is spontaneously disconnected from the parachute upon landing. Unless the payload is spontaneously disconnected from the parachute upon landing there is an unacceptable high risk that the payload is dragged by winds engaging the parachute, making retrieval of the parachuted payload extremely difficult and dangerous, if not impossible. Furthermore, there is a significant danger that the parachuted payload is toppled over while being dragged resulting in damage or loss of the parachuted payload such as a vehicle.

Several parachute ground disconnecting devices have been developed for automatically disconnecting a parachuted load upon landing. Such devices are designed as a coupler between the parachute and the payload for safely connecting the payload to the parachute during descent. Upon landing a payload weight dependent force acting on the parachute ground disconnecting device decreases and the device opens allowing disconnection of the payload form the parachute.

However, when designing a parachute ground disconnecting device there is a significant problem to overcome. In the first few seconds after parachute deployment transient parachute inflation phenomena generate substantial oscillations of the payload weight dependent force—or tension—acting on the parachute ground disconnecting device. Lowering the Release Load Percentage (RLP)—the ratio of the tension at the instant of disconnection to the tension during steady descent—to, for example, below 25% results in the parachute ground disconnecting device not spontaneously disconnecting upon landing, or not disconnecting at all when the parachute is caught by high winds. On the other hand, increasing the RLP to, for example, 40% to ensure spontaneous disconnecting upon landing, results in an unacceptable high risk of disconnection while the payload is still airborne.

This problem has been successfully overcome by the parachute ground disconnecting device disclosed in U.S. Pat. No. 5,687,931. Here, the parachute ground disconnecting device is kept in a locked position by a timer for a predetermined time interval during the initial portion of deployment, i.e. during the time period of the parachute inflation. After elapse of the predetermined time interval the device is set to disconnect when the tension is below a predetermined threshold or RLP. A version—GD500—operable in a payload range between 75 lbs and 500 lbs of this parachute ground disconnecting device has been successfully employed in numerous applications and under various—extreme—conditions. The GD500 has proven to be a simply operable and highly reliable parachute ground disconnecting device.

It would be advantageous to satisfy an increasing need for providing a simply operable and highly reliable parachute ground disconnecting device for heavy payload ranges between 2,000 lbs and 10,000 lbs and, ultimately, for payloads greater than 60,000 lbs.

SUMMARY OF THE INVENTION

It is, therefore, an object of the invention to provide a parachute ground disconnecting device for heavy payloads that is simply operable and highly reliable.

It is further an object of the invention to employ the proven GD500 in the heavy payload parachute ground disconnecting device as actuator.

It is yet further an object of the invention to provide a heavy payload parachute ground disconnecting device that is simple to manufacture.

In accordance with the present invention there is provided a parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising:

-   a supporting structure comprising:     -   a connecting mechanism for connecting the same to one of the         parachute and the payload;     -   a passage disposed such that, in a holding position,         accommodation therein of a link assembly for connecting the         supporting structure to one of the parachute and the payload is         enabled and such that disengagement of the link assembly from         the supporting structure is enabled for disconnecting the         payload from the parachute; -   an actuator mounted at a first end to the supporting structure and     comprising a holding mechanism at a second opposite end, the first     end and the second end a predetermined variable distance     therebetween, the distance being variable between a minimum and a     maximum value in dependence upon a force acting on the actuator     along its longitudinal axis, the actuator for keeping the holding     mechanism in a locked position during a predetermined time interval     and after elapse of the predetermined time interval for releasing     the holding mechanism when the force acting on the actuator is below     a predetermined threshold; and, -   a latch mechanism pivotally movable mounted to the supporting     structure and having an interacting structure for being accommodated     in the holding mechanism, in the holding position a pivot of the     latch mechanism and the interacting structure being disposed on     opposite sides of the passage, the latch mechanism for retaining the     link assembly in the holding position and for transferring a     predetermined portion of a payload force for acting on the actuator     within an operational range of the same, the latch mechanism being     movable such that the predetermined distance varies in dependence     upon the predetermined portion of the payload force and such that     the same is moved into an open position by the link assembly upon     release of the interacting structure from the holding mechanism.

In accordance with the present invention there is further provided a parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising:

-   a supporting structure comprising:     -   a connecting mechanism for connecting the same to one of the         parachute and the payload;     -   a passage disposed such that, in a holding position,         accommodation therein of a link assembly for connecting the         supporting structure to one of the parachute and the payload is         enabled and such that disengagement of the link assembly from         the supporting structure is enabled for disconnecting the         payload from the parachute;     -   a mounting structure for mounting an actuator, the actuator for         being mounted at a first end to the supporting structure and         comprising a holding mechanism at a second opposite end, the         first end and the second end having a predetermined variable         distance therebetween, the distance being variable between a         minimum and a maximum value in dependence upon a force acting on         the actuator along its longitudinal axis, the actuator for         keeping the holding mechanism in a locked position during a         predetermined time interval and after elapse of the         predetermined time interval for releasing the holding mechanism         when the force acting on the actuator is below a predetermined         threshold; and, -   a latch mechanism pivotally movable mounted to the supporting     structure and having an interacting structure for being accommodated     in a holding mechanism of the actuator, in the holding position a     pivot of the latch mechanism and the interacting structure being     disposed on opposite sides of the passage, the latch mechanism for     retaining the link assembly in the holding position and for     transferring a predetermined portion of a payload force for acting     on the actuator within an operational range of the same, the latch     mechanism being movable such that the predetermined distance varies     in dependence upon the predetermined portion of the payload force     and such that the same is moved into an open position by the link     assembly upon release of the interacting structure from the holding     mechanism.

In accordance with the present invention there is yet further provided a parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising:

-   a supporting structure comprising:     -   a connecting mechanism for connecting the same to one of the         parachute and the payload;     -   a passage disposed such that, in a holding position,         accommodation therein of a link assembly for connecting the         supporting structure to one of the parachute and the payload is         enabled and such that disengagement of the link assembly from         the supporting structure is enabled for disconnecting the         payload from the parachute; -   an actuator mounted at a first end to the supporting structure and     comprising a holding mechanism at a second opposite end, the first     end and the second end having a predetermined variable distance     therebetween, the distance being variable between a minimum and a     maximum value in dependence upon a force acting on the actuator     along its longitudinal axis, the actuator for keeping the holding     mechanism in a locked position during a predetermined time interval     and after elapse of the predetermined time interval for releasing     the holding mechanism when the force acting on the actuator is below     a predetermined threshold; and, -   a latch mechanism comprising:     -   a first lever pivotally movable mounted to the supporting         structure at a first end and having a first interacting surface         at a second opposite end, in the holding position the first         lever being disposed such that the first end and the second end         are located on opposite sides of the passage;     -   a second lever pivotally movable mounted to the supporting         structure at a first end and having at a second opposite end an         interacting structure for being accommodated in the holding         mechanism, the second lever having a second interacting surface         disposed between the first end and the second end, the second         interacting surface for interacting with the first interacting         surface in the holding position; -   the latch mechanism for retaining the link assembly in the holding     position and for transferring a predetermined portion of a payload     force for acting on the actuator within an operational range of the     same, the first and the second lever of the latch mechanism being     movable such that the predetermined distance varies in dependence     upon the predetermined portion of the payload force and such that     the first and the second lever are moved into an open position by     the link assembly upon release of the interacting structure from the     holding mechanism.

BRIEF DESCRIPTION OF THE FIGURES

Exemplary embodiments of the invention will now be described in conjunction with the following drawings, in which:

FIGS. 1 a to 1 c are simplified block diagrams schematically illustrating a cross-sectional view of a heavy payload parachute ground disconnecting device according to the invention in different stages of operation;

FIGS. 1 d and 1 e are simplified block diagrams schematically illustrating movement of various components of the heavy payload parachute ground disconnecting device according to the invention;

FIGS. 2 a and 2 b are simplified block diagrams schematically illustrating a cross-sectional view and a side view of the second lever of the heavy payload parachute ground disconnecting device according to the invention;

FIGS. 3 a and 3 b are simplified block diagrams schematically illustrating a cross-sectional view and a top view of the first lever of the heavy payload parachute ground disconnecting device according to the invention;

FIG. 4 is a simplified block diagram schematically illustrating a perspective view of the heavy payload parachute ground disconnecting device according to the invention;

FIGS. 5 a to 5 c are simplified block diagrams schematically illustrating transfer of a payload force to the actuator of the heavy payload parachute ground disconnecting device according to the invention;

FIG. 6 is a simplified block diagram schematically illustrating a detail of a second embodiment of the heavy payload parachute ground disconnecting device according to the invention; and

FIGS. 7 to 9 are simplified block diagrams illustrating a cross-sectional view of a third, fourth, and fifth embodiment of the heavy payload parachute ground disconnecting device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 a to 1 c, a cross sectional view of a preferred embodiment of a heavy payload parachute ground disconnecting device 100 according to the invention is shown in three stages of operation, in a holding position, in a transient position shortly after release, and in an open position, respectively. While the invention will be described employing a GD 500 parachute ground disconnecting device as actuator 102 for simplicity, it will become apparent to those of skill in the art that the heavy payload parachute ground disconnecting device 100 is easily modified for employing as actuator 102 other devices providing a similar functionality. The heavy payload parachute ground disconnecting device 100 comprises a supporting structure 104. Disposed in an upper portion of the supporting structure 104 is a connecting mechanism 106 for connecting the supporting structure 104 to a parachute. The connecting mechanism 106 is, for example, constructed as a cylindrical bore for accommodating a cylindrical bolt therein. Disposed in a lower portion of the supporting structure 104 is a passage 108 for accommodating—in the holding position—a link assembly 110 therein. The link assembly 110 connects the supporting structure 104 to a payload and comprises, for example, a cylindrical bolt for accommodation in the passage 108. Further, the passage 108 is designed such that in the open position, as shown in FIG. 1 c, disengagement of the link assembly 110 from the supporting structure 104 is enabled for disconnecting the payload from the parachute. The passage 108 comprises a substantially straight channel wide enough for enabling unobstructed movement of the link assembly 110 therethrough. Preferably, the channel is oriented substantially parallel to a line connecting the connecting mechanism 106 and the link assembly 110 in the holding position. The passage 108 further comprises a bent channel portion and an end portion. The end portion is formed to accommodate, in the holding position, the link assembly 110 therein, for example, having walls of cylindrical shape. Reasons for employing a bent channel portion will be provided below. As will become apparent, for some applications it is possible to omit the bent channel portion and to provide only a straight channel with an end portion. The link assembly 110 is retained in the holding position by a first lever 112 of a latch mechanism. The first lever 112 is pivotally movable mounted at a first end to the supporting structure 104 in pivot 114, for example, using cylindrical bores for accommodating a cylindrical bolt therein. At a second opposite end the first lever 112 has a first interacting surface 116, which is preferably of curved shape having a predetermined radius, for interacting with a second interacting surface 120 of a second lever 122. As shown in FIG. 1 a the first lever is disposed such that the pivot 114 and the interacting surface 116 are disposed on opposite sides of the passage 108. Preferably, the first lever 112 comprises an indentation 118, for example, of curved shape to accommodate a portion of the surface of a cylindrical bolt of the link assembly 110, for securing the link assembly 110 in the holding position, particularly during parachute inflation, as discussed above. The second lever 122 is pivotally movable mounted at a first end to the supporting structure 104 in pivot 124, for example, using cylindrical bores for accommodating a cylindrical bolt therein. At a second opposite end the second lever 122 comprises an interacting structure 126 for being accommodated, in the holding position, in a holding mechanism 128 of the actuator 102. Preferably, the second interacting surface 120 is a substantially flat surface disposed between the pivot 124 and the interacting structure 126 such that, in the holding position, it is oriented substantially perpendicular to a line connecting the connecting mechanism 106 and the link assembly 110. The actuator 102 is, preferably pivotally movable, mounted to the supporting structure 104 in pivot 130, for example, using cylindrical bores for accommodating a cylindrical bolt therein. A distance DA of the actuator—and subsequently the distance between the pivot 130 and the holding mechanism 128—is variable between a minimum and a maximum value in dependence upon a force FA—tension—acting on the actuator 102 along its longitudinal axis.

The actuator 102 keeps the holding mechanism 128 in a locked position, as shown in FIG. 1 a, during a predetermined time interval covering the period of parachute inflation. After elapse of the predetermined time interval the actuator releases the holding mechanism 128, as shown in FIG. 1 b, when the force FA acting on the actuator 102 is below a predetermined threshold—RLP.

The first lever 112 of the latch mechanism retains the link assembly 110 in the holding position, as shown in FIG. 1 a, and transfers in concert with the second lever 122 a predetermined portion—force FA—of a payload dependent force FP, acting on the link assembly 110, via the interacting structure 126 as tension to the holding mechanism 128 of the actuator 102, as shown in FIG. 1 d. In order to ensure that the force FA is acting on the actuator in a proper fashion, the second lever 122 is designed such that a circle 140 around the pivot 124 with a radius R corresponding to the distance between the pivot 124 and the interacting structure 126 is touched tangentially by a line 142 connecting the pivot 130 and the holding mechanism 128. Further, the first lever 112 and the second lever 122 are designed such that, in the holding position, the interacting structure 126 moves—in dependence upon the force FA—approximately along the line 142 a distance DA between a maximum value I and a minimum value II, as shown in FIG. 1 e. To ensure proper movement of the latch mechanism and the actuator 102, it is preferred to mount the actuator 102 pivotally movable. Furthermore, the indentation 118 and the end portion of the passage 108 are designed such that vertical movement of the link assembly 110 corresponding to the movement of the first lever 112 between positions I and II is enabled and such that the link assembly 110 is securely retained in the indentation 118 during parachute inflation.

In operation, the link assembly 110 is retained in the holding position by the indentation 118 of the first lever 112 and the end portion of the passage 108. During the first portion of the descent, the holding mechanism 128 of the actuator 102 is locked for a predetermined time interval set using timer 150 and covering the time span of parachute inflation. After elapse of the predetermined time interval—during steady descent—the holding mechanism 128 is unlocked. During the phase of steady descent the latch mechanism is approximately in position I resulting in a maximum value of the distance DA. Upon landing the payload force FP is decreasing resulting in a movement from position I to position II corresponding to a minimum value of the distance DA. When the distance DA reaches the minimum value—which corresponds to the RLP—the holding mechanism 128 opens and releases the interacting structure 126, as shown in FIG. 1 b. The remaining force FP acting on the first lever 112 pushes the same down, which in turn pushes the second lever 122 down enabling the second end of the first lever 112 to pass interacting element 121 of the second lever 122. After the first lever 112 and the second lever 122 are in an open position, as shown in FIG. 1 c, the link assembly 110 is able to move freely through the passage 108 for disengaging from the supporting structure 104. Preferably, opening movement of the first lever 112 and the second lever 122 is limited by stoppers 132 and 134, respectively, to avoid obstruction of the movement of link assembly 110 by the first lever 112 and the second lever 122 ensuring proper disengagement of the link assembly 110 from the supporting structure 104. Optionally, stopper 136 is provided to limit movement of the actuator 102 after opening.

Referring to FIGS. 2 a and 2 b, a cross-sectional view and a side view AA of the second lever 122 are shown, respectively. The second lever 122 comprises two parallel lever sections 122A and 122B, with each of the lever sections having a bore 124 for being separately mounted to the supporting structure 104. Interposed between the lever sections 122A and 122B is the interacting structure 126 and the interacting element 121. Referring to FIGS. 3 a and 3 b, a cross-sectional view and a top view BB of the first lever 112 are shown, respectively. The first lever 112 comprises an interacting section 112A, which is narrower than a remaining portion 112B in order to fit between the lever sections 122A and 122B of the second lever 122 for interacting with the interacting element 121. Further, the remaining portion—line 112C—is designed such that it passes the first end of the second lever 122 during opening. Curvature of the interacting surface 116 is, preferably, designed such that friction between the first interacting surface 116 and the second interacting surface 120 and wear of the first interacting surface 116 are within predetermined limits. The second lever is manufactured from a single cast piece or, alternatively, from several pieces such as the lever sections 122A and 122B, the interacting element 121, and the interacting structure 126 mounted together. Preferably, the first lever 112 and the second lever 122 are made of heat treated stainless steel to reduce wear of interacting portions and to protect against corrosion.

In the preferred embodiment the support structure 104 comprises two support plates 104A and 104B mounted together in parallel and having a predetermined distance therebetween, as shown in the perspective view of FIG. 4. Preferably, the support plates 104A and 104B are made of steel to ensure sufficient strength.

It is noted that the various components of the heavy payload parachute ground disconnecting device 100 are designed to withstand 4G forces—encountered during the parachute inflation.

The two-lever design of the heavy payload parachute ground disconnecting device 100 is highly advantageous by providing a relatively simple, yet highly flexible design for various payload ranges. Referring to FIGS. 5 a to 5 c, the following simplified calculations enable a first design approach of the levers for a given payload range. For the calculation it is assumed that the payload force FP acts along a line connecting the connecting mechanism 106 and the link assembly 110, which is oriented substantially vertical—y-axis—during steady descent. As shown in FIG. 5 a, a force FD acting on the first interacting surface 116 in point D in dependence upon the payload force FP acting on the first lever 112 in point C is determined as: FD=FP×D1/D2   (1) wherein D1 is a distance between a center of the pivot 114 and a center of the link assembly 110, and D2 is a distance between the center of the pivot 114 and the interacting point D. The force FD is transmitted at the interaction point D to the second interacting surface 120 of the second lever 122. Having regard to FIG. 5 b, a force FE acting on the interacting structure 126 is then determined as: FE=FD×D3/D4   (2) wherein D3 is a distance between a center of the pivot 124 and interacting point D, and D4 is a distance between the center of the pivot 124 and a center of the interacting structure 126. The force FE is acting in vertical direction, as shown in FIG. 5 b. Referring to FIG. 5 c, the force FA acting on the actuator 102 along the line 142 is then determined as a component of the force FE as follows: FA=FE×cos γ  (3) wherein γ is the angle between the line 142 and the vertical y-axis. Combining equations (1), (2), and (3) results in equation (4) describing the tension FA acting on the actuator 102 in dependence upon the payload force FP as follows: FA=FP×D1/D2×D3/D4×cos γ.   (4)

As is evident from equation (4) the design of the heavy payload parachute ground disconnecting device 100 is easily adaptable to a wide range of payloads. For example, it enables use of the GD 500 parachute disconnecting device as actuator by transforming a payload force FP in a range between 2,000 lbs to 10,000 lbs into a tension FA in a range between 75 lbs and 500 lbs, but is not limited thereto. Varying the ratios D1/D2 and D3/D4 enables design of the heavy load parachute ground disconnecting devices in various payload ranges above 10,000 lbs with ultimate payload range above 60,000 lbs. It is noted, that in order to minimize the size of the device 100 it is preferred to minimize D1 in equation (4), since there are limits to minimizing D3 in order to enable the first lever 112 to pass the second lever 122 during opening. Due to a given size of the link assembly 110 and the bolt of pivot 114 it is likely that a bent channel portion needs to be incorporated into the passage 108 to minimize D1, as shown in FIGS. 5 a to 5 c. A further—limited—design factor in equation (4) is the angle γ. However, varying the angle γ to optimize load reduction—i.e. having an angle γ close to 90°—is difficult if not impossible to implement. Therefore, the angle γ is more likely to be determined by considerations regarding optimized placement of the actuator 102 in order to minimize the size of the device 100 and to ensure proper access to the timer 150 and the holding mechanism 128.

Optionally, a further payload reduction is achieved by retaining, in the holding position, the link assembly 110 using the first lever 112 as well as the surface of the end portion of the passage 108, i.e. the payload force FP is distributed between the first lever 112 and the supporting structure 104 substantially depending on an angle between a contact surface of the passage 108 and a vertical y-axis. However, this embodiment is not preferred since it is difficult to ensure proper distribution of the payload force FP, which is also likely to change with time due to wear of the contact surface of the passage 108. Further, to reduce the wear of the contact surface of the passage 108 it is likely that the supporting structure 104 needs to be made of heat treated steel.

In one application, the heavy payload parachute ground disconnecting device 100 has been designed for transforming a payload range between 2,000 lbs to 10,000 lbs into a tension FA range between 75 lbs and 500 lbs for use of the GD 500 as actuator. A RLP range of the heavy load parachute ground disconnecting device 100 has been set to be between 18% and 28% of any payload in the range between 2,000 lbs to 10,000 lbs, i.e. the device 100 may disconnect at 28% of the payload and must disconnect when the payload force FP is reduced to 18% of the payload. The GD 500 allows presetting of different RLPs by the manufacturer. Further, the levers of the heavy payload parachute ground disconnecting device 100 have been designed to vary the distance DA of the actuator 102 between a maximum value of 0.375″ and a minimum value of 0.125″ as specified for the GD 500. As is evident, the design of the heavy payload parachute ground disconnecting device 100 is easily adaptable to accommodate different payload ranges, different tension FA, and values for the distance DA.

The heavy payload parachute ground disconnecting device 100 is easily rigged using, for example, the following procedure:

-   -   inserting an end loop of a parachute in the connecting mechanism         106 and securing the bolt of the connecting mechanism 106;     -   inserting an end loop of a payload in the link assembly 110 and         securing the bolt of the link assembly 110;     -   securing the actuator 102 to the support structure 104 using a         bolt as pivot 130 and securing the same;     -   setting the time interval by adjusting the timer 150 of the         actuator 102;     -   opening the first lever 112 and the second lever 122 and moving         the bolt of the link assembly 110 through the passage into the         holding position;     -   moving the first lever 112 and the second lever 122 into the         holding position; and     -   locking the interacting structure 126 by closing the holding         mechanism 128 of the actuator.

Referring to FIG. 6, a detail of second embodiment 200 of the heavy payload parachute ground disconnecting device according to the invention is shown. Here, a second lever 222 comprises an elongated structure allowing the first lever 112 to pass the same during opening along a line 152. While the lever 222 is of simpler design than the lever 122, simplifying manufacture from a single cast piece, it has a pivot 224 at a substantially lower position requiring enlargement of the support structure 104 as well as the link assembly 110.

Referring to FIG. 7, a third embodiment 300 of the heavy payload parachute ground disconnecting device according to the invention is shown. The latch mechanism of heavy load parachute ground disconnecting device 300 comprises only one lever 312 pivotally movable mounted to the support structure 104 in pivot 314. Here, the lever 312 is directly interacting with the holding mechanism 128 of the actuator 102 via interacting element 326. While this design is simpler than the two lever design above it is likely limited to applications for lighter payloads, since heavier payloads likely necessitate an unwanted large lever and subsequently an unwanted large device.

Referring to FIG. 8, a fourth embodiment 400 of the heavy payload parachute ground disconnecting device according to the invention is shown. Here, a first lever 412 and correspondingly a support structure 404 comprise two bores 414 and 414A for enabling varying of a pivot of the first lever 412. This embodiment allows adjustment of the payload range in the field by inserting a bolt in respective bores 414 and 414A, i.e. the bore 414A for a lighter payload range and the bore 414 for a heavier payload range. While it is likely that this embodiment requires an enlarged support structure 404 than respective devices operable in only a single payload range, it increases flexibility.

Referring to FIG. 9, a fifth embodiment 500 of the heavy payload parachute ground disconnecting device according to the invention is shown. Here, the connecting mechanism 506 is connected to a payload instead of a parachute, while the link assembly 510 is connected to the parachute. The embodiment 500 is basically the heavy payload parachute ground disconnecting device 100 used “upside-down”. While the heavy payload parachute ground disconnecting device 100 is disconnected from the payload and carried by the parachute after disconnection, the embodiment 500 stays with the payload. Preferably, the embodiment 500 comprises a spring loaded first lever 112 and a spring loaded second lever 122 using, for example, tension springs 560 and 562 in order to ensure proper opening movement of the levers and subsequently unobstructed disengagement of the link assembly 510 from the support structure 104.

The heavy payload parachute ground disconnecting device and its various embodiments are highly advantageous by providing a simple, yet highly flexible, design for numerous payload ranges. Furthermore, incorporation of the GD 500 provides a heavy payload parachute ground disconnecting device based on proven and reliable technology.

Numerous other embodiments of the invention will be apparent to persons skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims. 

1. A parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising: a supporting structure comprising: a connecting mechanism for connecting the same to one of the parachute and the payload; a passage disposed such that, in a holding position, accommodation therein of a link assembly for connecting the supporting structure to one of the parachute and the payload is enabled and such that disengagement of the link assembly from the supporting structure is enabled for disconnecting the payload from the parachute; an actuator mounted at a first end to the supporting structure and comprising a holding mechanism at a second opposite end, the first end and the second end having a predetermined variable distance therebetween, the distance being variable between a minimum and a maximum value in dependence upon a force acting on the actuator along its longitudinal axis, the actuator for keeping the holding mechanism in a locked position during a predetermined time interval and after elapse of the predetermined time interval for releasing the holding mechanism when the force acting on the actuator is below a predetermined threshold; and, a latch mechanism pivotally movable mounted to the supporting structure and having an interacting structure for being accommodated in the holding mechanism, in the holding position a pivot of the latch mechanism and the interacting structure being disposed on opposite sides of the passage, the latch mechanism for retaining the link assembly in the holding position and for transferring a predetermined portion of a payload force for acting on the actuator within an operational range of the same, the latch mechanism being movable such that the predetermined distance varies in dependence upon the predetermined portion of the payload force and such that the same is moved into an open position by the link assembly upon release of the interacting structure from the holding mechanism.
 2. A parachute ground disconnecting device as defined in claim 1 wherein the latch mechanism comprises a single lever mounted to the supporting structure at a first end and having the interacting structure at a second opposite end.
 3. A parachute ground disconnecting device as defined in claim 1 wherein the latch mechanism comprises two interacting levers.
 4. A parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising: a supporting structure comprising: a connecting mechanism for connecting the same to one of the parachute and the payload; a passage disposed such that, in a holding position, accommodation therein of a link assembly for connecting the supporting structure to one of the parachute and the payload is enabled and such that disengagement of the link assembly from the supporting structure is enabled for disconnecting the payload from the parachute; a mounting structure for mounting an actuator, the actuator for being mounted at a first end to the supporting structure and comprising a holding mechanism at a second opposite end, the first end and the second end having a predetermined variable distance therebetween, the distance being variable between a minimum and a maximum value in dependence upon a force acting on the actuator along its longitudinal axis, the actuator for keeping the holding mechanism in a locked position during a predetermined time interval and after elapse of the predetermined time interval for releasing the holding mechanism when the force acting on the actuator is below a predetermined threshold; and, a latch mechanism pivotally movable mounted to the supporting structure and having an interacting structure for being accommodated in a holding mechanism of the actuator, in the holding position a pivot of the latch mechanism and the interacting structure being disposed on opposite sides of the passage, the latch mechanism for retaining the link assembly in the holding position and for transferring a predetermined portion of a payload force for acting on the actuator within an operational range of the same, the latch mechanism being movable such that the predetermined distance varies in dependence upon the predetermined portion of the payload force and such that the same is moved into an open position by the link assembly upon release of the interacting structure from the holding mechanism.
 5. A parachute ground disconnecting device as defined in claim 4 wherein the latch mechanism comprises a single lever mounted to the supporting structure at a first end and having the interacting structure at a second opposite end.
 6. A parachute ground disconnecting device as defined in claim 4 wherein the latch mechanism comprises a two interacting levers.
 7. A parachute ground disconnecting device as defined in claim 6 wherein the latch mechanism comprises: a first lever pivotally movable mounted to the supporting structure at a first end and having a first interacting surface at a second opposite end, in the holding position the first lever being disposed such that the first end and the second end are located on opposite sides of the passage; and, a second lever pivotally movable mounted to the supporting structure at a first end and having at a second opposite end an interacting structure for being accommodated in the holding mechanism, the second lever having a second interacting surface disposed between the first end and the second end, the second interacting surface for interacting with the first interacting surface in the holding position;
 8. A parachute ground disconnecting device for disconnecting a parachuted payload from a parachute upon landing comprising: a supporting structure comprising: a connecting mechanism for connecting the same to one of the parachute and the payload; a passage disposed such that, in a holding position, accommodation therein of a link assembly for connecting the supporting structure to one of the parachute and the payload is enabled and such that disengagement of the link assembly from the supporting structure is enabled for disconnecting the payload from the parachute; an actuator mounted at a first end to the supporting structure and comprising a holding mechanism at a second opposite end, the first end and the second end having a predetermined variable distance therebetween, the distance being variable between a minimum and a maximum value in dependence upon a force acting on the actuator along its longitudinal axis, the actuator for keeping the holding mechanism in a locked position during a predetermined time interval and after elapse of the predetermined time interval for releasing the holding mechanism when the force acting on the actuator is below a predetermined threshold; and, a latch mechanism comprising: a first lever pivotally movable mounted to the supporting structure at a first end and having a first interacting surface at a second opposite end, in the holding position the first lever being disposed such that the first end and the second end are located on opposite sides of the passage; a second lever pivotally movable mounted to the supporting structure at a first end and having at a second opposite end an interacting structure for being accommodated in the holding mechanism, the second lever having a second interacting surface disposed between the first end and the second end, the second interacting surface for interacting with the first interacting surface in the holding position; the latch mechanism for retaining the link assembly in the holding position and for transferring a predetermined portion of a payload force for acting on the actuator within an operational range of the same, the first and the second lever of the latch mechanism being movable such that the predetermined distance varies in dependence upon the predetermined portion of the payload force and such that the first and the second lever are moved into an open position by the link assembly upon release of the interacting structure from the holding mechanism.
 9. A parachute ground disconnecting device as defined in claim 8 wherein the actuator is pivotally movable.
 10. A parachute ground disconnecting device as defined in claim 8 wherein the passage comprises a substantially straight channel oriented substantially parallel to a line connecting the connecting mechanism and the link assembly in the holding position.
 11. A parachute ground disconnecting device as defined in claim 10 wherein the channel comprises an angled portion.
 12. A parachute ground disconnecting device as defined in claim 8 wherein the first lever comprises an indentation for retaining a portion of the link assembly therein.
 13. A parachute ground disconnecting device as defined in claim 12 wherein an end portion of the passage and the indentation substantially form a bore such that movement of the first lever between a position corresponding to a maximum value of the predetermined distance and a position corresponding to a minimum value of the predetermined distance is enabled and such that the link assembly is securely retained in the indentation during parachute inflation.
 14. A parachute ground disconnecting device as defined in claim 8 wherein the first interacting surface is a curved surface having a predetermined radius.
 15. A parachute ground disconnecting device as defined in claim 8 wherein the second surface is a flat surface oriented substantially perpendicular to the line connecting the connecting mechanism and the link assembly in the holding position.
 16. A parachute ground disconnecting device as defined in claim 8 wherein the second lever comprises two parallel lever sections disposed at a predetermined distance and having the interacting structure and an interacting element interposed therebetween, the interacting element comprising the second interacting surface.
 17. A parachute ground disconnecting device as defined in claim 16 wherein each of the two lever sections comprises a bore for separately mounting each of the two lever sections to the supporting structure.
 18. A parachute ground disconnecting device as defined in claim 16 wherein a portion of the first lever comprising the first interacting surface has a width to fit between the two lever sections.
 19. A parachute ground disconnecting device as defined in claim 8 wherein the support structure comprises two parallel plates mounted together having a predetermined distance therebetween.
 20. A parachute ground disconnecting device as defined in claim 19 wherein the actuator and the latch mechanism are disposed between the two plates.
 21. A parachute ground disconnecting device as defined in claim 8 comprising a first stop pin for stopping the first lever in an open position and a second stop pin for stopping the second lever in an open position.
 22. A parachute ground disconnecting device as defined in claim 21 wherein the first lever and the second lever are spring loaded. 